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rfc:rfc9062



Internet Engineering Task Force (IETF) S. Salam Request for Comments: 9062 A. Sajassi Category: Informational Cisco ISSN: 2070-1721 S. Aldrin

                                                                Google
                                                              J. Drake
                                                               Juniper
                                                       D. Eastlake 3rd
                                                             Futurewei
                                                             June 2021
         Framework and Requirements for Ethernet VPN (EVPN)
         Operations, Administration, and Maintenance (OAM)

Abstract

 This document specifies the requirements and reference framework for
 Ethernet VPN (EVPN) Operations, Administration, and Maintenance
 (OAM).  The requirements cover the OAM aspects of EVPN and Provider
 Backbone Bridge EVPN (PBB-EVPN).  The framework defines the layered
 OAM model encompassing the EVPN service layer, network layer,
 underlying Packet Switched Network (PSN) transport layer, and link
 layer but focuses on the service and network layers.

Status of This Memo

 This document is not an Internet Standards Track specification; it is
 published for informational purposes.
 This document is a product of the Internet Engineering Task Force
 (IETF).  It represents the consensus of the IETF community.  It has
 received public review and has been approved for publication by the
 Internet Engineering Steering Group (IESG).  Not all documents
 approved by the IESG are candidates for any level of Internet
 Standard; see Section 2 of RFC 7841.
 Information about the current status of this document, any errata,
 and how to provide feedback on it may be obtained at
 https://www.rfc-editor.org/info/rfc9062.

Copyright Notice

 Copyright (c) 2021 IETF Trust and the persons identified as the
 document authors.  All rights reserved.
 This document is subject to BCP 78 and the IETF Trust's Legal
 Provisions Relating to IETF Documents
 (https://trustee.ietf.org/license-info) in effect on the date of
 publication of this document.  Please review these documents
 carefully, as they describe your rights and restrictions with respect
 to this document.  Code Components extracted from this document must
 include Simplified BSD License text as described in Section 4.e of
 the Trust Legal Provisions and are provided without warranty as
 described in the Simplified BSD License.

Table of Contents

 1.  Introduction
   1.1.  Relationship to Other OAM Work
   1.2.  Specification of Requirements
   1.3.  Terminology
 2.  EVPN OAM Framework
   2.1.  OAM Layering
   2.2.  EVPN Service OAM
   2.3.  EVPN Network OAM
   2.4.  Transport OAM for EVPN
   2.5.  Link OAM
   2.6.  OAM Interworking
 3.  EVPN OAM Requirements
   3.1.  Fault Management Requirements
     3.1.1.  Proactive Fault Management Functions
       3.1.1.1.  Fault Detection (Continuity Check)
       3.1.1.2.  Defect Indication
         3.1.1.2.1.  Forward Defect Indication (FDI)
         3.1.1.2.2.  Reverse Defect Indication (RDI)
     3.1.2.  On-Demand Fault Management Functions
       3.1.2.1.  Connectivity Verification
       3.1.2.2.  Fault Isolation
   3.2.  Performance Management
     3.2.1.  Packet Loss
     3.2.2.  Packet Delay and Jitter
 4.  Security Considerations
 5.  IANA Considerations
 6.  References
   6.1.  Normative References
   6.2.  Informative References
 Acknowledgements
 Authors' Addresses

1. Introduction

 This document specifies the requirements and defines a reference
 framework for Ethernet VPN (EVPN) Operations, Administration, and
 Maintenance (OAM) [RFC6291].  In this context, we use the term "EVPN
 OAM" to loosely refer to the OAM functions required for and/or
 applicable to [RFC7432] and [RFC7623].
 EVPN is a Layer 2 VPN (L2VPN) solution for multipoint Ethernet
 services with advanced multihoming capabilities that uses BGP for
 distributing Customer/Client Media Access Control (C-MAC) address
 reachability information over the core MPLS/IP network.
 PBB-EVPN combines Provider Backbone Bridging (PBB) [IEEE-802.1Q] with
 EVPN in order to reduce the number of BGP MAC advertisement routes;
 provide client MAC address mobility using C-MAC [RFC7623] aggregation
 and Backbone MAC (B-MAC) [RFC7623] sub-netting; confine the scope of
 C-MAC learning to only active flows; offer per-site policies; and
 avoid C-MAC address flushing on topology changes.
 This document focuses on the fault management and performance
 management aspects of EVPN OAM.  It defines the layered OAM model
 encompassing the EVPN service layer, network layer, underlying Packet
 Switched Network (PSN) transport layer, and link layer but focuses on
 the service and network layers.

1.1. Relationship to Other OAM Work

 This document leverages concepts and draws upon elements defined
 and/or used in the following documents:
 [RFC6136] specifies the requirements and a reference model for OAM as
 it relates to L2VPN services, pseudowires, and associated Packet
 Switched Network (PSN) tunnels.  This document focuses on Virtual
 Private LAN Service (VPLS) and Virtual Private Wire Service (VPWS)
 solutions and services.
 [RFC8029] defines mechanisms for detecting data plane failures in
 MPLS Label Switched Paths (LSPs), including procedures to check the
 correct operation of the data plane as well as mechanisms to verify
 the data plane against the control plane.
 [IEEE-802.1Q] specifies the Ethernet Connectivity Fault Management
 (CFM) protocol, which defines the concepts of Maintenance Domains,
 Maintenance Associations, Maintenance End Points, and Maintenance
 Intermediate Points.
 [Y.1731] extends Connectivity Fault Management in the following
 areas: it defines fault notification and alarm suppression functions
 for Ethernet and specifies mechanisms for Ethernet performance
 management, including loss, delay, jitter, and throughput
 measurement.

1.2. Specification of Requirements

 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
 "OPTIONAL" in this document are to be interpreted as described in
 BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
 capitals, as shown here.

1.3. Terminology

 This document uses the following terminology, much of which is
 defined in [RFC6136]:
 CE          Customer Edge device; for example, a host, router, or
             switch.
 CFM         Connectivity Fault Management [IEEE-802.1Q]
 DF          Designated Forwarder [RFC7432]
 Down MEP    A MEP that originates traffic away from and terminates
             traffic towards the core of the device in whose port it
             is logically located.
 EVI         An EVPN instance spanning the Provider Edge (PE) devices
             participating in that EVPN [RFC7432].
 L2VPN       Layer 2 VPN
 LOC         Loss of continuity
 MA          Maintenance Association; a set of MEPs belonging to the
             same Maintenance Domain (MD) established to verify the
             integrity of a single service instance [IEEE-802.1Q].
 MD          Maintenance Domain; an OAM Domain that represents a
             region over which OAM frames can operate unobstructed
             [IEEE-802.1Q].
 MEP         Maintenance End Point; it is responsible for origination
             and termination of OAM frames for a given MA.  A MEP is
             logically located in a device's port [IEEE-802.1Q].
 MIP         Maintenance Intermediate Point; it is located between
             peer MEPs and can process and respond to certain OAM
             frames but does not initiate them.  A MIP is logically
             located in a device's port [IEEE-802.1Q].
 MP2P        Multipoint to Point
 NMS         Network Management Station [RFC6632]
 P           Provider network interior (non-edge) node
 P2MP        Point to Multipoint
 PBB         Provider Backbone Bridge [RFC7623]
 PE          Provider Edge network device
 Up MEP      A MEP that originates traffic towards and terminates
             traffic from the core of the device in whose port it is
             logically located.
 VPN         Virtual Private Network

2. EVPN OAM Framework

2.1. OAM Layering

 Multiple layers come into play for implementing an L2VPN service
 using the EVPN family of solutions as listed below.  The focus of
 this document is the service and network layers.
  • The service layer runs end to end between the sites or Ethernet

segments that are being interconnected by the EVPN solution.

  • The network layer extends between the EVPN PE (Provider Edge)

nodes and is mostly transparent to the P (provider network

    interior) nodes (except where flow entropy comes into play).  It
    leverages MPLS for service (i.e., EVI) multiplexing and split-
    horizon functions.
  • The transport layer is dictated by the networking technology of

the PSN. It may be based on either MPLS LSPs or IP.

  • The link layer is dependent upon the physical technology used.

Ethernet is a popular choice for this layer, but other

    alternatives are deployed (e.g., Packet over SONET (POS), Dense
    Wavelength Division Multiplexing (DWDM), etc.).
 This layering extends to the set of OAM protocols that are involved
 in the ongoing maintenance and diagnostics of EVPN networks.
 Figure 1 below depicts the OAM layering and shows which devices have
 visibility into what OAM layer(s).
         +---+                               +---+
 +--+    |   |    +---+    +---+    +---+    |   |    +--+
 |CE|----|PE |----| P |----| P |----| P |----|PE |----|CE|
 +--+    |   |    +---+    +---+    +---+    |   |    +--+
         +---+                               +---+
   o-------o----------- Service OAM -----------o-------o
           o----------- Network OAM -----------o
           o--------o--------o--------o--------o  Transport OAM
    o----o   o----o   o----o   o----o   o----o   o----o  Link OAM
                         Figure 1: OAM Layering
 Service OAM and Network OAM mechanisms only have visibility to the PE
 nodes but not the P nodes.  As such, they can be used to deduce
 whether the fault is in the customer's own network, the local CE-PE
 segment, the PE-PE segment, or the remote CE-PE segment(s).  EVPN
 Transport OAM mechanisms can be used for fault isolation between the
 PEs and P nodes.
 Figure 2 below shows an example network where Ethernet domains are
 interconnected via EVPN using MPLS, and it shows the OAM mechanisms
 that are applicable at each layer.  The details of the layers are
 described in the sections below.
         +---+                               +---+
 +--+    |   |    +---+    +---+    +---+    |   |    +--+
 |CE|----|PE |----| P |----| P |----| P |----|PE |----|CE|
 +--+    |   |    +---+    +---+    +---+    |   |    +--+
         +---+                               +---+
    o----o---------- CFM (Service OAM) ----------o----o
           o-------- EVPN Network OAM ---------o
           o--------o--------o--------o--------o MPLS OAM
    o----o   o----o   o----o   o----o   o----o   o----o 802.3 OAM
                                                        [IEEE-802.3]
                       Figure 2: EVPN OAM Example

2.2. EVPN Service OAM

 The EVPN Service OAM protocol depends on what service-layer
 technology is being interconnected by the EVPN solution.  In the case
 of [RFC7432] and [RFC7623], the service layer is Ethernet; hence, the
 corresponding Service OAM protocol is Ethernet CFM [IEEE-802.1Q].
 EVPN Service OAM is visible to the CEs and EVPN PEs but not to the P
 nodes.  This is because the PEs operate at the Ethernet MAC layer in
 [RFC7432] and [RFC7623], whereas the P nodes do not.
 The EVPN PE MUST support MIP functions in the applicable Service OAM
 protocol (for example, Ethernet CFM).  The EVPN PE SHOULD support MEP
 functions in the applicable Service OAM protocol.  This includes both
 Up and Down MEP functions.
 As shown in Figure 3, the MIP and MEP functions being referred to are
 logically located within the device's port operating at the customer
 level.  (There could be MEPs/MIPs within PE ports facing the provider
 network, but they would not be relevant to EVPN Service OAM as the
 traffic passing through them will be encapsulated/tunneled, so any
 customer-level OAM messages will just be treated as data.)  Down MEP
 functions are away from the core of the device while Up MEP functions
 are towards the core of the device (towards the PE forwarding
 mechanism in the case of a PE).  OAM messages between the PE Up MEPs
 shown are a type of EVPN Network OAM, while such messages between the
 CEs or from a PE to its local CE or to the remote CE are Service
 OAMs.
  +-------+   +----------------+       +----------------+   +-------+
  |+-----+|   |+--------------+|       |+--------------+|   |+-----+|
  ||  CE ||   ||     PE       ||  ...  ||       PE     ||   || CE  ||
  |+--+--+|   |+---+--------+-+|       |+-+--------+---+|   |+--+--+|
  |   |   |   |    |        |  |       |  |        |    |   |   |   |
  |+--+--+|   |+---+-----+  .  |       |  .  +-----+---+|   |+--+--+|
  || MEP ||   ||   | Up ^|  .  |  ...  |  .  | Up ^|   ||   || MEP ||
  ||DownV||   ||MIP|MEP  |  .  |       |  .  |MEP  |MIP||   ||DownV||
  |+--+--+|   ||   |DownV|  .  |       |  .  |DownV|   ||   |+--+--+|
  |   |   |   |+---+-----+  |  |       |  |  +-----+---+|   |   |   |
  +---|---+   +----|--------|--+       +--|--------|----+   +---|---+
      |            |        |             |        |            |
      +------------+        +---  ...  ---+        +------------+
                         Figure 3: CFM Details
 The EVPN PE MUST, by default, learn the MAC address of locally
 attached CE MEPs by snooping on CFM frames and advertising them to
 remote PEs as a MAC/IP Advertisement route.  Some means to limit the
 number of MAC addresses that a PE will learn SHOULD be implemented.
 The EVPN PE SHOULD advertise any MEP/MIP local to the PE as a MAC/IP
 Advertisement route.  Since these are not subject to mobility, they
 SHOULD be advertised with the static (sticky) bit set (see
 Section 15.2 of [RFC7432]).

2.3. EVPN Network OAM

 EVPN Network OAM is visible to the PE nodes only.  This OAM layer is
 analogous to Virtual Circuit Connectivity Verification (VCCV)
 [RFC5085] in the case of VPLS/VPWS.  It provides mechanisms to check
 the correct operation of the data plane as well as a mechanism to
 verify the data plane against the control plane.  This includes the
 ability to perform fault detection and diagnostics on:
  • the MP2P tunnels used for the transport of unicast traffic between

PEs. EVPN allows for three different models of unicast label

    assignment: label per EVI, label per <ESI, Ethernet Tag>, and
    label per MAC address.  In all three models, the label is bound to
    an EVPN Unicast Forwarding Equivalence Class (FEC).  EVPN Network
    OAM MUST provide mechanisms to check the operation of the data
    plane and verify that operation against the control plane view.
  • the MP2P tunnels used for aliasing unicast traffic destined to a

multihomed Ethernet segment. The three label assignment models,

    discussed above, apply here as well.  In all three models, the
    label is bound to an EVPN Aliasing FEC.  EVPN Network OAM MUST
    provide mechanisms to check the operation of the data plane and
    verify that operation against the control plane view.
  • the multicast tunnels (either MP2P or P2MP) used for the transport

of broadcast, unknown unicast, and multicast traffic between PEs.

    In the case of ingress replication, a label is allocated per EVI
    or per <EVI, Ethernet Tag> and is bound to an EVPN Multicast FEC.
    In the case of Label Switched Multicast (LSM) and, more
    specifically, aggregate inclusive trees, again, a label may be
    allocated per EVI or per <EVI, Ethernet Tag> and is bound to the
    tunnel FEC.
  • the correct operation of the Ethernet Segment Identifier (ESI)

split-horizon filtering function. In EVPN, a label is allocated

    per multihomed Ethernet segment for the purpose of performing the
    access split-horizon enforcement.  The label is bound to an EVPN
    Ethernet segment.
  • the correct operation of the Designated Forwarder (DF) [RFC7432]

filtering function. EVPN Network OAM MUST provide mechanisms to

    check the operation of the data plane and verify that operation
    against the control plane view for the DF filtering function.
 EVPN Network OAM mechanisms MUST provide in-band monitoring
 capabilities.  It is desirable, to the extent practical, for OAM test
 messages to share fate with data messages.  Details of how to achieve
 this are beyond the scope of this document.
 EVPN Network OAM SHOULD provide both proactive and on-demand
 mechanisms of monitoring the data plane operation and data plane
 conformance to the state of the control plane.

2.4. Transport OAM for EVPN

 The Transport OAM protocol depends on the nature of the underlying
 transport technology in the PSN.  MPLS OAM mechanisms [RFC8029]
 [RFC6425] as well as ICMP [RFC0792] and ICMPv6 [RFC4443] are
 applicable, depending on whether the PSN employs MPLS or IP
 transport, respectively.  Furthermore, Bidirectional Forwarding
 Detection (BFD) mechanisms per [RFC5880], [RFC5881], [RFC5883], and
 [RFC5884] apply.  Also, the BFD mechanisms pertaining to MPLS-TP LSPs
 per [RFC6428] are applicable.

2.5. Link OAM

 Link OAM depends on the data-link technology being used between the
 PE and P nodes.  For example, if Ethernet links are employed, then
 Ethernet Link OAM ([IEEE-802.3], Clause 57) may be used.

2.6. OAM Interworking

 When interworking two networking domains, such as actual Ethernet and
 EVPN to provide an end-to-end emulated service, there is a need to
 identify the failure domain and location, even when a PE supports
 both the Service OAM mechanisms and the EVPN Network OAM mechanisms.
 In addition, scalability constraints may not allow the running of
 proactive monitoring, such as Ethernet Continuity Check Messages
 (CCMs) [IEEE-802.1Q], at a PE to detect the failure of an EVI across
 the EVPN domain.  Thus, the mapping of alarms generated upon failure
 detection in one domain (e.g., actual Ethernet or EVPN network
 domain) to the other domain is needed.  There are also cases where a
 PE may not be able to process Service OAM messages received from a
 remote PE over the PSN even when such messages are defined, as in the
 Ethernet case, thereby necessitating support for fault notification
 message mapping between the EVPN Network domain and the Service
 domain.
 OAM interworking is not limited, though, to scenarios involving
 disparate network domains.  It is possible to perform OAM
 interworking across different layers in the same network domain.  In
 general, alarms generated within an OAM layer, as a result of
 proactive fault detection mechanisms, may be injected into its
 client-layer OAM mechanisms.  This allows the client-layer OAM to
 trigger event-driven (i.e., asynchronous) fault notifications.  For
 example, alarms generated by the Link OAM mechanisms may be injected
 into the Transport OAM layer, and alarms generated by the Transport
 OAM mechanism may be injected into the Network OAM mechanism, and so
 on.
 EVPN OAM MUST support interworking between the Network OAM and
 Service OAM mechanisms.  EVPN OAM MAY support interworking among
 other OAM layers.

3. EVPN OAM Requirements

 This section discusses the EVPN OAM requirements pertaining to fault
 management and performance management.

3.1. Fault Management Requirements

3.1.1. Proactive Fault Management Functions

 The network operator configures proactive fault management functions
 to run periodically.  Certain actions (for example, protection
 switchover or alarm indication signaling) can be associated with
 specific events, such as entering or clearing fault states.

3.1.1.1. Fault Detection (Continuity Check)

 Proactive fault detection is performed by periodically monitoring the
 reachability between service end points, i.e., MEPs in a given MA,
 through the exchange of CCMs [IEEE-802.1Q].  The reachability between
 any two arbitrary MEPs may be monitored for:
  • in-band, per-flow monitoring. This enables per-flow monitoring

between MEPs. EVPN Network OAM MUST support fault detection with

    per-user flow granularity.  EVPN Service OAM MAY support fault
    detection with per-user flow granularity.
  • a representative path. This enables a liveness check of the nodes

hosting the MEPs, assuming that the loss of continuity (LOC) to

    the MEP is interpreted as a failure of the hosting node.  This,
    however, does not conclusively indicate liveness of the path(s)
    taken by user data traffic.  This enables node failure detection
    but not path failure detection through the use of a test flow.
    EVPN Network OAM and Service OAM MUST support fault detection
    using test flows.
  • all paths. For MPLS/IP networks with ECMP, the monitoring of all

unicast paths between MEPs (on non-adjacent nodes) may not be

    possible since the per-hop ECMP hashing behavior may yield
    situations where it is impossible for a MEP to pick flow entropy
    characteristics that result in exercising the exhaustive set of
    ECMP paths.  The monitoring of all ECMP paths between MEPs (on
    non-adjacent nodes) is not a requirement for EVPN OAM.
 The fact that MPLS/IP networks do not enforce congruency between
 unicast and multicast paths means that the proactive fault detection
 mechanisms for EVPN networks MUST provide procedures to monitor the
 unicast paths independently of the multicast paths.  This applies to
 EVPN Service OAM and Network OAM.

3.1.1.2. Defect Indication

 Defect indications can be categorized into two types: forward and
 reverse, as described below.  EVPN Service OAM MUST support at least
 one of these types of event-driven defect indications upon the
 detection of a connectivity defect.

3.1.1.2.1. Forward Defect Indication (FDI)

 FDI is used to signal a failure that is detected by a lower-layer OAM
 mechanism.  A server MEP (i.e., an actual or virtual MEP) transmits a
 forward defect indication in a direction away from the direction of
 the failure (refer to Figure 4 below).
                            Failure
                               |
        +-----+      +-----+   V   +-----+      +-----+
        |  A  |------|  B  |--XXX--|  C  |------|  D  |
        +-----+      +-----+       +-----+      +-----+
            <===========|             |============>
              Forward                    Forward
              Defect                     Defect
              Indication                 Indication
                  Figure 4: Forward Defect Indication
 Forward defect indication may be used for alarm suppression and/or
 for the purpose of interworking with other layer OAM protocols.
 Alarm suppression is useful when a transport-level or network-level
 fault translates to multiple service- or flow-level faults.  In such
 a scenario, it is enough to alert a network management station (NMS)
 of the single transport-level or network-level fault in lieu of
 flooding that NMS with a multitude of Service or Flow granularity
 alarms.  EVPN PEs SHOULD support forward defect indication in the
 Service OAM mechanisms.

3.1.1.2.2. Reverse Defect Indication (RDI)

 RDI is used to signal that the advertising MEP has detected a LOC
 defect.  RDI is transmitted in the direction of the failure (refer to
 Figure 5).
                            Failure
                               |
        +-----+      +-----+   V   +-----+      +-----+
        |  A  |------|  B  |--XXX--|  C  |------|  D  |
        +-----+      +-----+       +-----+      +-----+
            |===========>             <============|
              Reverse                    Reverse
              Defect                     Defect
              Indication                 Indication
                  Figure 5: Reverse Defect Indication
 RDI allows single-sided management, where the network operator can
 examine the state of a single MEP and deduce the overall health of a
 monitored service.  EVPN PEs SHOULD support reverse defect indication
 in the Service OAM mechanisms.  This includes both the ability to
 signal a LOC defect to a remote MEP as well as the ability to
 recognize RDI from a remote MEP.  Note that, in a multipoint MA, RDI
 is not a useful indicator of unidirectional fault.  This is because
 RDI carries no indication of the affected MEP(s) with which the
 sender had detected a LOC defect.

3.1.2. On-Demand Fault Management Functions

 On-demand fault management functions are initiated manually by the
 network operator and continue for a bounded time period.  These
 functions enable the operator to run diagnostics to investigate a
 defect condition.

3.1.2.1. Connectivity Verification

 EVPN Network OAM MUST support on-demand connectivity verification
 mechanisms for unicast and multicast destinations.  The connectivity
 verification mechanisms SHOULD provide a means for specifying and
 carrying the following in the messages:
  • variable-length payload/padding to test connectivity problems

related to the Maximum Transmission Unit (MTU).

  • test frame formats as defined in Appendix C of [RFC2544] to detect

potential packet corruption.

 EVPN Network OAM MUST support connectivity verification at per-flow
 granularity.  This includes both user flows (to test a specific path
 between PEs) as well as test flows (to test a representative path
 between PEs).
 EVPN Service OAM MUST support connectivity verification on test flows
 and MAY support connectivity verification on user flows.
 For multicast connectivity verification, EVPN Network OAM MUST
 support reporting on:
  • the DF filtering status of a specific port(s) or all the ports in

a given bridge domain.

  • the split-horizon filtering status of a specific port(s) or all

the ports in a given bridge domain.

3.1.2.2. Fault Isolation

 EVPN OAM MUST support an on-demand fault localization function.  This
 involves the capability to narrow down the locality of a fault to a
 particular port, link, or node.  The characteristic of forward/
 reverse path asymmetry in MPLS/IP makes fault isolation a direction-
 sensitive operation.  That is, given two PEs A and B, localization of
 continuity failures between them requires running fault-isolation
 procedures from PE A to PE B as well as from PE B to PE A.
 EVPN Service OAM mechanisms only have visibility to the PEs but not
 the MPLS or IP P nodes.  As such, they can be used to deduce whether
 the fault is in the customer's own network, the local CE-PE segment,
 or a remote CE-PE segment(s).  EVPN Network and Transport OAM
 mechanisms can be used for fault isolation between the PEs and P
 nodes.

3.2. Performance Management

 Performance management functions can be performed both proactively
 and on demand.  Proactive management involves a recurring function,
 where the performance management probes are run continuously without
 a trigger.  We cover both proactive and on-demand functions in this
 section.

3.2.1. Packet Loss

 EVPN Network OAM SHOULD provide mechanisms for measuring packet loss
 for a given service -- for example, [RFC7680] and [RFC6673].
 Given that EVPN provides inherent support for multipoint-to-
 multipoint connectivity, packet loss cannot be accurately measured by
 means of counting user data packets.  This is because user packets
 can be delivered to more PEs or more ports than are necessary (e.g.,
 due to broadcast, unpruned multicast, or unknown unicast flooding).
 As such, a statistical means of approximating the packet loss rate is
 required.  This can be achieved by sending "synthetic" OAM packets
 that are counted only by those ports (MEPs) that are required to
 receive them.  This provides a statistical approximation of the
 number of data frames lost, even with multipoint-to-multipoint
 connectivity.

3.2.2. Packet Delay and Jitter

 EVPN Service OAM SHOULD support measurement of one-way and two-way
 packet delay and delay variation (jitter) across the EVPN network.
 Measurement of one-way delay requires clock synchronization between
 the probe source and target devices.  Mechanisms for clock
 synchronization are outside the scope of this document.  Note that
 Service OAM performance management mechanisms defined in [Y.1731] can
 be used.  See also [RFC7679], [RFC2681], and [RFC3393].
 EVPN Network OAM MAY support measurement of one-way and two-way
 packet delay and delay variation (jitter) across the EVPN network.

4. Security Considerations

 EVPN OAM MUST prevent OAM packets from leaking outside of the EVPN
 network or outside their corresponding Maintenance Domain.  This can
 be done for CFM, for example, by having MEPs implement a filtering
 function based on the Maintenance Level associated with received OAM
 packets.
 EVPN OAM SHOULD provide mechanisms for implementation and optional
 use to:
  • prevent denial-of-service attacks caused by exploitation of the

OAM message channel (for example, by forging messages to exceed a

    Maintenance End Point's capacity to maintain state).
  • authenticate communicating end points (for example, MEPs and

MIPs).

5. IANA Considerations

 This document has no IANA actions.

6. References

6.1. Normative References

 [RFC0792]  Postel, J., "Internet Control Message Protocol", STD 5,
            RFC 792, DOI 10.17487/RFC0792, September 1981,
            <https://www.rfc-editor.org/info/rfc792>.
 [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
            Requirement Levels", BCP 14, RFC 2119,
            DOI 10.17487/RFC2119, March 1997,
            <https://www.rfc-editor.org/info/rfc2119>.
 [RFC4443]  Conta, A., Deering, S., and M. Gupta, Ed., "Internet
            Control Message Protocol (ICMPv6) for the Internet
            Protocol Version 6 (IPv6) Specification", STD 89,
            RFC 4443, DOI 10.17487/RFC4443, March 2006,
            <https://www.rfc-editor.org/info/rfc4443>.
 [RFC5880]  Katz, D. and D. Ward, "Bidirectional Forwarding Detection
            (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010,
            <https://www.rfc-editor.org/info/rfc5880>.
 [RFC5881]  Katz, D. and D. Ward, "Bidirectional Forwarding Detection
            (BFD) for IPv4 and IPv6 (Single Hop)", RFC 5881,
            DOI 10.17487/RFC5881, June 2010,
            <https://www.rfc-editor.org/info/rfc5881>.
 [RFC5883]  Katz, D. and D. Ward, "Bidirectional Forwarding Detection
            (BFD) for Multihop Paths", RFC 5883, DOI 10.17487/RFC5883,
            June 2010, <https://www.rfc-editor.org/info/rfc5883>.
 [RFC5884]  Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow,
            "Bidirectional Forwarding Detection (BFD) for MPLS Label
            Switched Paths (LSPs)", RFC 5884, DOI 10.17487/RFC5884,
            June 2010, <https://www.rfc-editor.org/info/rfc5884>.
 [RFC6291]  Andersson, L., van Helvoort, H., Bonica, R., Romascanu,
            D., and S. Mansfield, "Guidelines for the Use of the "OAM"
            Acronym in the IETF", BCP 161, RFC 6291,
            DOI 10.17487/RFC6291, June 2011,
            <https://www.rfc-editor.org/info/rfc6291>.
 [RFC6425]  Saxena, S., Ed., Swallow, G., Ali, Z., Farrel, A.,
            Yasukawa, S., and T. Nadeau, "Detecting Data-Plane
            Failures in Point-to-Multipoint MPLS - Extensions to LSP
            Ping", RFC 6425, DOI 10.17487/RFC6425, November 2011,
            <https://www.rfc-editor.org/info/rfc6425>.
 [RFC6428]  Allan, D., Ed., Swallow, G., Ed., and J. Drake, Ed.,
            "Proactive Connectivity Verification, Continuity Check,
            and Remote Defect Indication for the MPLS Transport
            Profile", RFC 6428, DOI 10.17487/RFC6428, November 2011,
            <https://www.rfc-editor.org/info/rfc6428>.
 [RFC7432]  Sajassi, A., Ed., Aggarwal, R., Bitar, N., Isaac, A.,
            Uttaro, J., Drake, J., and W. Henderickx, "BGP MPLS-Based
            Ethernet VPN", RFC 7432, DOI 10.17487/RFC7432, February
            2015, <https://www.rfc-editor.org/info/rfc7432>.
 [RFC7623]  Sajassi, A., Ed., Salam, S., Bitar, N., Isaac, A., and W.
            Henderickx, "Provider Backbone Bridging Combined with
            Ethernet VPN (PBB-EVPN)", RFC 7623, DOI 10.17487/RFC7623,
            September 2015, <https://www.rfc-editor.org/info/rfc7623>.
 [RFC8029]  Kompella, K., Swallow, G., Pignataro, C., Ed., Kumar, N.,
            Aldrin, S., and M. Chen, "Detecting Multiprotocol Label
            Switched (MPLS) Data-Plane Failures", RFC 8029,
            DOI 10.17487/RFC8029, March 2017,
            <https://www.rfc-editor.org/info/rfc8029>.
 [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
            2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
            May 2017, <https://www.rfc-editor.org/info/rfc8174>.

6.2. Informative References

 [IEEE-802.1Q]
            IEEE, "IEEE Standard for Local and metropolitan area
            networks--Bridges and Bridged Networks", IEEE Std 802.1Q-
            2014, DOI 10.1109/IEEESTD.2014.6991462, December 2014,
            <https://doi.org/10.1109/IEEESTD.2014.6991462>.
 [IEEE-802.3]
            IEEE, "IEEE Standard for Ethernet", IEEE Std 802.3-2018,
            DOI 10.1109/IEEESTD.2018.8457469, August 2018,
            <https://doi.org/10.1109/IEEESTD.2018.8457469>.
 [RFC2544]  Bradner, S. and J. McQuaid, "Benchmarking Methodology for
            Network Interconnect Devices", RFC 2544,
            DOI 10.17487/RFC2544, March 1999,
            <https://www.rfc-editor.org/info/rfc2544>.
 [RFC2681]  Almes, G., Kalidindi, S., and M. Zekauskas, "A Round-trip
            Delay Metric for IPPM", RFC 2681, DOI 10.17487/RFC2681,
            September 1999, <https://www.rfc-editor.org/info/rfc2681>.
 [RFC3393]  Demichelis, C. and P. Chimento, "IP Packet Delay Variation
            Metric for IP Performance Metrics (IPPM)", RFC 3393,
            DOI 10.17487/RFC3393, November 2002,
            <https://www.rfc-editor.org/info/rfc3393>.
 [RFC5085]  Nadeau, T., Ed. and C. Pignataro, Ed., "Pseudowire Virtual
            Circuit Connectivity Verification (VCCV): A Control
            Channel for Pseudowires", RFC 5085, DOI 10.17487/RFC5085,
            December 2007, <https://www.rfc-editor.org/info/rfc5085>.
 [RFC6136]  Sajassi, A., Ed. and D. Mohan, Ed., "Layer 2 Virtual
            Private Network (L2VPN) Operations, Administration, and
            Maintenance (OAM) Requirements and Framework", RFC 6136,
            DOI 10.17487/RFC6136, March 2011,
            <https://www.rfc-editor.org/info/rfc6136>.
 [RFC6632]  Ersue, M., Ed. and B. Claise, "An Overview of the IETF
            Network Management Standards", RFC 6632,
            DOI 10.17487/RFC6632, June 2012,
            <https://www.rfc-editor.org/info/rfc6632>.
 [RFC6673]  Morton, A., "Round-Trip Packet Loss Metrics", RFC 6673,
            DOI 10.17487/RFC6673, August 2012,
            <https://www.rfc-editor.org/info/rfc6673>.
 [RFC7679]  Almes, G., Kalidindi, S., Zekauskas, M., and A. Morton,
            Ed., "A One-Way Delay Metric for IP Performance Metrics
            (IPPM)", STD 81, RFC 7679, DOI 10.17487/RFC7679, January
            2016, <https://www.rfc-editor.org/info/rfc7679>.
 [RFC7680]  Almes, G., Kalidindi, S., Zekauskas, M., and A. Morton,
            Ed., "A One-Way Loss Metric for IP Performance Metrics
            (IPPM)", STD 82, RFC 7680, DOI 10.17487/RFC7680, January
            2016, <https://www.rfc-editor.org/info/rfc7680>.
 [Y.1731]   ITU-T, "Operation, administration and maintenance (OAM)
            functions and mechanisms for Ethernet-based networks",
            ITU-T Recommendation G.8013/Y.1731, August 2015.

Acknowledgements

 The authors would like to thank the following for their review of
 this work and their valuable comments: David Black, Martin Duke, Xiao
 Min, Gregory Mirsky, Zaheduzzaman Sarker, Dave Schinazi, John
 Scudder, Melinda Shore, Robert Wilton, Alexander Vainshtein, Stig
 Venaas, and Éric Vyncke.

Authors' Addresses

 Samer Salam
 Cisco
 The Atrium Building, Floor 3
 Weygand St.
 Beirut
 Lebanon
 Email: ssalam@cisco.com
 Ali Sajassi
 Cisco
 170 West Tasman Drive
 San Jose, CA 95134
 United States of America
 Email: sajassi@cisco.com
 Sam Aldrin
 Google, Inc.
 1600 Amphitheatre Parkway
 Mountain View, CA 94043
 United States of America
 Email: aldrin.ietf@gmail.com
 John E. Drake
 Juniper Networks
 1194 N. Mathilda Ave.
 Sunnyvale, CA 94089
 United States of America
 Email: jdrake@juniper.net
 Donald E. Eastlake 3rd
 Futurewei Technologies
 2386 Panoramic Circle
 Apopka, FL 32703
 United States of America
 Phone: +1-508-333-2270
 Email: d3e3e3@gmail.com
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